Lifting mechanism



Jan, 1G, 1933. l. VON K. HOTT LIFTING MECHANI SM 2 Sheets-Sheet l Filed Aug. 20, 1930 /N VEN TOR.

b/ON VON KEE'THOTT Jan. M), 1933. 1. VON K; HOTT LIFTING MECHANSM Filed Aug. 20, 1930 2 Sheets-Sheerl 2 /7/15 TOR/VEY Patented Jan. 10, 1933 UNITED STATES PAT orrics ION VON KERT HOTT, OF DAYTON, OHIO, ASSIGNOR TO THE JOYCE-CRIDLAND COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO LIFTING MECHANISM Application led August 20, 1930. Serial No. 476,468.

rlhis invention relates to lifting mechanisms and more particularly to an electrically operated lifting jack.

One object of the invention is to provide such a lifting mechanism with a simple efficient device for automatically opening the switch and interrupting the operation of the motor when the lifting element reaches the limit of its movement in the direction in which it has been started. v

A further object of the invention is to provide means for quickly checking the movement of the motor after the switch has been opened.

A further object of the invention is to provide such a lifting mechanism with a device whichwill function as an air circulating device t0 cool the motor while the switch is closed and will function as a retarding device to check the movement of the motor when the switch is opened.

ther objects of the invention will appear as the mechanism is described in detail. y

In the accompanying drawings Fig. 1 is a vertical sectional view taken centrally through a lifting mechanism embodying my invention and showing a part of the apparatus in elevation; Fig. 2 is a'section taken `on the line 2 2 of Fig. 1, showing the! motor controlling mechanismin plan; Fig. 3 is a transverse section taken on the line 3 3 of Fig. 1; Fig. 4 is a plan view of the motor casing with the switch actuating device removed; Fig. 5 is a section taken on the line 5 5 of Fig. 1; Fig. 6 is a sectional view of the switch casing taken on the line 6 6 of Fig. 2; Fig. 7 is a transverse section taken through the switch casing on the line 7 7 of Fig. 1; Fig. 8 is a sectional detail view of the connecting device between the switch and the switch actuating device; and Fig. 9 is a diagrammatic view of the switch.

In these drawings I have illustrated one embodiment of my invention and have shown the same as applied to a lifting jack of a well known type. It will be understood, however, that this particular embodiment has been chosen for the purpose of illustration only and that the mechanism may take various forms and may be applied to lifting mechanisms of various kinds.

In that form here illustrated the jack comprises a hollow standard 10 mounted on a base 11 and having mounted therein a vertically movable lifting element or ram 12 which is provided at its lower end with the usual nut 13 to receive the actuating screw 14 which is rotatably mounted on the base 11. Rigidly connected with the screw is a beveled gear 15 which meshes with a beveled pinion 16 mounted kon a stud shaft 17 journaled in a bearing 18 carried by a removable plate 19 secured to one side of the standard and serving to close an opening which provides access t0 the interior thereof. Rigidly secured to the shaft 17 is a spur gear 20 which is connected through an idler 21 with a pinion 22 on a shaft 23 which is journaled in suitable bearings in the standard and in the plate 19. The pinion 22 is arranged on the inner side of the plate 19and on the outer side of that plate the shaft 23 carries a frame 24 arranged within a housing 25 and having mounted thereon a plurality of planetary gears 24a which are arranged between and mesh with an internal gear 25a and an inner or sun gear 27 the latter being carried by a spur gear' 26 rotatably mounted within the housingl 25. The

spur gear 26 is driven by a pinion-28 on a shaft 29`which extends beyond the housing 25 and is provided with'a beveled'gear 30 which meshes with a beveled pinion 31 on the lower end of the shaft .32 of a motor 33 which is mounted within a motor casing 34. The motor casing and the gear casing 25 are rigidly connected one to the other and are supported on the standard and its base. 'Ihe gearing interposed between the motor and the yscrew constitutes the operating mechanism for the screw and serves to reduce the motor speed to that required for operating the screw.

The motor 33 is a reversible electric motor and the circuits therefor are controlled by a switch mounted in a switch casing 35 arranged above the gear casing 25. This switch may be of any suitable character which will reverse the operation of the motor. As here shown, it comprises a rotatable element 36 mounted for rotation about a vertical axis and preferably carried by a shaft 37 mounted in the upper and lower walls of the switch casing 35. This rotatable element is provided with two sets of contact members 38, 38a, 38?) and 39 adapted to be moved into and out of engagement with stationary contact members 40, 40a, 406, 41 and 41a, respectively. The arrangement is such that when the rotatable member is in an intermediate or neutral position the movable contact members Will be out of engagement with the iXed contact members and the circuit through the motor will be broken. IVhen the rotatable member is moved in one direction the circuit will be closed to rotate the motor in one direction and when the rotatable member is moved from its neutral position in the other direction the circuit will be closed through the motor so as to cause the same to rotate in the opposite direction. In the present instance, I have illustrated in Fig. 9 a three phase switch of such a character that each line will be broken at two places, but it will be understood that neither characteristic is essential to the invention. Then the shaft 37 is moved in a counterclockwise direction the line C will be connected through contacts 40, 38a, 386 and 40a to the line C and the line B will be connected through 401), 38, 39 and 41a with the line B', thus causing the motor to rotate in one direction. When the shaft 37 is moved in a clockwise direction from its neutral position the line C will be connected through P contacts 40, 38. 39 and 41 to the line B and the line B will be connected through contacts 40?), 381), 38a and 40a to the line C', thus causing the motor to rotate in an opposite direction. The switch shaft 37 extends above the housing 35 and has secured thereto an arm 42 by means of which it is connected with the switch actuating device, as will be hereinater described.

Means are provided for manually moving the switch from its neutral position into either of its operative positions and, if desired,

the switch may be restored manually to its neutral position but to prevent damage to the mechanism due to continued operation of the motor after the lifting element has reached the limit of its movement I have provided means for automatically restoring the switch to its neutral position as soon as the lifting element reaches the limit of its movement in either direction. For this purpose I have provided a switch actuating device which, in the present instance, is mounted on the motor casing 34 and comprises a linger vpiece or handle 43 pivotally mounted on the stud 44. Rigidly connected with the handle 43 and extending in opposite directions from the axis thereof are arms 45 and 46. The arm 46 is connected with the switch arm 42 by means of a rod 47 which is pivotally connected with the arm 46 and is slidably connected with the switch arm 42, preferably by extending the same through a stud 48 carried by the outer end oi the arm 42. Springs 49 and 50 are coiled about the rod 47 on opposite sides of the stud 48 and are confined between the same and suitable stops, such as collars 51, secured to the rod. These springs serve to resist the movement of the rod 47 with relation to thc switch arm 42, in either direction. The switch itselt is yieldably held in the position to which it has been moved, this being accomplished in the present apparatuslby rigidly securing to the switch shaft 37 a plate 52 having notches 53, 54 and 55 arranged to be engaged by the tapered end of a spring pressed plunger y56. lhen the switch is in its neutral position the plunger will engage the recess 55 and yieldably retain the switch in that position. When the switch is moved yto one of its operative positions the plunger will engage in either the notch 53 or the notch 54. In any instance the yieldable detent will hold the switch against movement until positive pressure has been applied thereto suicient to force the tapered end of the plunger or detent out of the recess.

Consequently when the switch actuating device is operated to move the actuating rod 47 in either direction the detent or retaining device 5G will resist the movement of the switch and will cause one of the springs, 49 or 50, depending upon the direction in which the rod 47 is moved, to be compressed until the ressure becomes great enough to force the detent 56 out of the notch in the plate 52. As soon as the detent is forced out of the notch the spring, 49 or 50, will expand and quickly move the switch-in the direction in which it has been started. The compression of the spring, 49 or 50, may be relied upon to impart initial movement to the switch but I prefer tov provide a positive connection between the rod and the switch arm which will become effective after the spring has been compressed sufficient-ly to impart the desired movement to the switch after the latter is released. For this purpose I have mounted about the rod 47, on opposite sides of the stud 48, sleeves or abutments 57 so arranged that they will be engaged by the collars 51 when the respective springs have been compressed to the desired extent, thus causing the switch arm to be positively moved by the rod.

In order to automatically restore the switch actuating device and the switch to their neutral positions the arm 45 of the switch actuating device is connected by a rod 58 with a rock arm 59 rigidly secured to a vertical shaft 60 mounted within the standard 10 and projecting through a slot 61 therein. This rod is journaled on bearings 62 and 63 near the upper and lower ends of the standard and has secured near the respective ends thereof collars 64 and 65 arranged to be engaged by a projection or pin 66 rigidly secured to the lower end of the lifting element 12. Each cam is so shaped that when engaged by the pin the shaft will be rocked in a direction to restore the switch actuating device vto its neutral position, thus opening the switch and interrupting' the operation of the motor just as the lifting element reaches the limitof its movement.

When the switch is opened to stop the motor the armature of the latter will continue to rotate for an interval due to its momentum and this movement will be transmi ted through the operating mechanism to the screw. In order to stop the motor after the switch has been opened I have provided a normally inoperative bralre which will be rendered operative by the opening of the switch. The braking device is of such a. character that when the motor is in operation it will function as an air circulating crevice to :torce air through the motor casing and cool the motor.y In that form of the apparatus here shown this combined braking and air circulating device is arranged at'the upper end of the motor casing, whichis shaped to form a supplemental fan casing or air chan ber 67 in which is mounted a fan GS which is connected with the motor shaft 32. Preterably the air chamber is cylindrical in torni and the fan comp rises an eccentrically mounted piston or dish 69 having radial slots in which are slidably mounted blades 7 0 which will be held in contact with the circumferential wall of the chamber by centrifugal torce when the motor is in operation. The upper end oi the motor casing is provided with a series of ports 7l, 72, 73 and 74 and the air chamber is closed at its upper end by a plate having openings, such as peripheral slots 76 and 77, to selectively connect the interior of the air chamber with the ports 7l to 74. The slots or openings 7 6 and 7 are arranged on the opposite sides of the point at which the eccentric disk engagesthe wall oi' the cylinder, so that one opening will serve as an inlet for the air chamber and the other opening will serve as an outlet therefor, depending upon the direction in which the tan rotates. The communication between the air chamber and the several ports is controlled by the switch actuating device i3 and that device is thereforeprovided with adislr-like base 78 which is rotatably mounted upon 'the upper Yend of the motor casing and extends over the several ports7l, 72, 73 and 74t.- 'At one side of its axis this base portion of the switch actuating device is provided with a conduit 79 arranged to connect the siot 7G in the cover for the air chamber withthe gort 71 when the switch actuating device is in one operative position and to connect the slot 77 with the port 72 when the switch actuating device is in its other operative position. VGn the other side of its axis the base 78 of the switch actuating device is provided with an arcuate conduit SOhaving an offset portion 81 so arranged that when the conduit 7 9 `is in line with the port 7l the part 8l of the conduit will be in line with the port 7 3 and when the conduit 7 9 is in line with the port 72 the part 8l will be in line with the port 74. The end portions oi' the arcuate conduit 8O are of such length that when the offset portion 8l thereof is in line with the port 73 one end portion of the conduit will be in line with the port 77 for the air chamber and when the offset portion 8l is in line with the port 74 the other end portion of the conduit will be in line with the slot 76 of the air chamber.

hen the switch actuating device is moved to its intermediate or neutral position the conduits 79 `and 80 will be out of line with all the ports and with the slots 7 6 and 77. Consequently when the switch actuating device is in one of its operative positions, for example the position shown in Fig. 3, the air chamber will be connected with the motor casing through the slot 7 6 port 71 on the one side and through the port 73 and the notch 77 on the other side. Therefore, the rotation of the'fan by the motor will cause the air to circulate through the motor casing. Then the switch actuating device is in its other operating position the circulation will be 1naintained in the same manner through the ports 72 and 74. l/Vhen the switch actuating device is moved to its intermediate or neutral position all the ports will be closed and the air cannot escape from the air chamber and will therefore resist the rotation of the fan Vand cause the device to act as a brake to overstandard, operating mechanism for said lifting element, a reversible electric motor to drive said operating mechanism, andl a switch to control the operation of said Inotor, an actuating device for said switch having a neutral position and two operative positions and having manually operable means for moving the same from said neutral position to either operative position, yieldaole means to retain said actuating device in the position to which it has been moved, and Vmeans controlled in accordance with the movement of said lifting element to automatically restore said switch actuating device to said neutral position when said lifting elementreaches the limit of its movement in either direction, said restoring means comprising apart adapted to yield until the resistance offered by said retaining means has been overcome and to then move said actuating device quickly to its neutral position.

2. In a lifting mechanism comprising a standard, a lifting element mounted on said standard, operating mechanism for said lifting element, a reversible electric motor to drive said operatingr mechanism, and a switch to control the operation of said motor, yieldable means to retain said switch in the position to which it has been moved, an actuating device for said switch having manually operable means for imparting movement thereto, means for connecting said actuating device with said switch comprising a yieldable device adapted toyield to tile initial resistance offered by said retaining device to the movement of said switch and to quickly actuate said switch when said resistance has been overcome, and means controlled in accordance with the movement of said lifting element to cause said switch actuating device to move said switch to a neutral position when said lifting element reaches the limit of its movement.

3. In a lifting mechanism comprising a standard, a lifting element mounted on said said standard, operating mechanism for said lifting element, a reversible electric motor to drive said operating mechanism, and a switch to control the operation of said motor, yiel-dable means to retain said switch in the position to which it has been moved, an arm operatively connected with said switch, a pivoted actuating device having manually operable means for imparting movement thereto and having arms extending in opposite directions from its axis, a rod pivotally connected with one arm of said switch actuating device and slidably connected with said switch arm, springs interposed between said rod and said switch arm to yieldably resist the movement of said rod in either direction with relation to said yswitch arm, and means acting on the other arm of said switch actuating device and controlled in accordance with the movement of said lifting element to cause said switch to be moved to a neutral position when said lifting element reaches the limit of its movement.

4. In a liftinT mechanism comprising a standard, a lifting element mounted on said standard, operating mechanism for said lifting element, a `reversible el ctric motor to drive said operating mechanism, and a s vitch to control the operation of said motor, yieldable means to retain said switch in the position to which it has been moved, an arm operatively connected with sait switch, a pivoted actuating device having manually operable means for imparting movement thereto and having arms extending in opposite directions from its axis, a rod pivotally connected with one arm of said switch actnating device and slidably connected with said switch arm, springs interposed between said rod and said switch arm to yieldably resist the movement of said rod in either direction with relation to said switch arm, a rotatory member, a rod connecting said rotatory member with the other arm of said switch actuating device, and means actuated by said lifting element to impart movement to said rotatory member as said lifting element approaches the limit of its movement in either direction.

5. In a lifting mechanism comprising a standard, a lifting eiement, operating mechanism for said Vlifting element, an electric motor to drive said operating mechanism, and a switch to control the operation of said motor, 'a normally inoperative brake for said motor, a switch actuating device, and means controlied by said switch actuating device to render said brake operative when said switch actuating device is moved to a tion to open said switch.

6. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an electric motor to drive said operating mechanism, and a switch to control the operation of said motor, a combined brake and air circulating device operatively connected with said motor, a switch operating device, and means controlled by said switch actuating device vto causey said combined device to function as an air circulating device when the switch is closed and to operate as a brake to check the movement of said motor when said switch is open.

7. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an electric motor to drive said operating mechanism and having a casing, and a switch to control the operation of said motor, an air circulating device having moans for connecting the same with said motor casing, a switch actuating device, and means controlled by said switch actuating device to control the connection between. said air circulating device and said motor casing.

8. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an electric motor to drive said operating mechanism and having a casing, and a switch to control the operation of said motor, an air chamber connected with said motor casing, a movable member mounted in said air chamber and connected with said inotor to canse air to circulate in said motor casing, a switch actuating device having a neutral position, and means controlled by said switch actuating device to interrupt the connection bctween said air chamber and said motor casing when said switch actuating device is moved to said neutral position and thus cause .having a casing, and a switch to controi said movable member to retard the movement of said motor.

9. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an electric motor to drive said operating mechanism and having a casing, and a switch to control the operation of said motor, a fan casing having a passageway leading to said motor casing, a fan mounted in said fan casing and connected with said motor', for rotation thereby, and a switch actuating device having means for so controlling said passageway that said fan will function as an air circulating device when said switch actuating device is in one position and will function as a brake when said switch actuating device is in another position.

l0. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an elect-ric motor to drive said operating mechanism and l the operation of said motor, a fan casing at one end of said motor' casing, a fan mounted in said fan casing and connected with said motor for rotation thereby, said motor casing having a plurality of ports adjacent to said fan casing, a member movably mounted on said motor casing and having means for connecting said ports with and disconnecting the same from said fan casing, means for operatively connecting said member with said switch, and means for actuating said member'.

ll. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an electric motor to drive said operating mechanism and having a casing, and a switch to control the operation of said motor, a fan casing at one end of said motor casing, a fan mounted in said fan casing and connected with said motor for rotation thereby, said motor casing having two pairs of ports adjacent to said fan casing, an actuating device for said switch mounted on said motor casing for movement into a neutral position or in either of two operative positions, said switch actuating device having means for connecting one pair of said ports with said fan casing when said switch actuating device is in one operative position, for connecting the other pair of ports with said fan casing when said switch actuating device is in its other operative position and for disconnecting both pairs of ports from said fan casing when said switch actuating device is in its neutral position.

l2. In a lifting mechanism comprising a standard, a lifting element, operating mechanism for said lifting element, an electric motor to drive said operating mechanism and having a casing, and a switch to control the operation of said motor, a fan casing arranged at one end of said motor casing and having two spaced openings in its outer end, a fan mounted in said fan casing and connected with said motor for rotation thereby, said motor casing having two pairs of ports spaced about said fan casing, a member rotatably mounted on said motor casing and overlapping said openings and said ports, means for connecting said member with said switch, said member having means for moving the same into either of two operative positions or into a neutral position, said member' also having two conduits so arranged that when said member is in one of said operative positions said conduits will connect the ports of one pair with the respective openings in said fan casing, and when said member is in its other operative position will connect the ports of the otner pair with openings of said fan casing and when said member is in its neutral position will disconnect all of said ports from said fan casing.

13. In a lifting mechanism comprising a standard, a lifting element mounted on said standard, operating mechanism for said lifting element, a reversible electric motor to drive said operating mechanism and a switch to control the operation of said motor, an oscillatory actuating device mounted separately from said switch, having a neutral position and two operative positions, and having manually operable means for moving the same from said neutral position to either operative position, connecting means between said actuating device and said switch to cause each movement of said actuating device to impart a like movement to said switch, and means controlled in accordance with the movement of said lifting element to automatically restore said switch actuating device to said neutral position when said lifting element reaches the limit of its movement in either direction.

In testimony whereof, I afx my signature hereto.

ION VON KERT HOTT. 

